| Copper(Cu)is an essential trace element for living organisms.However,intake of an excess amount of Cu will cause human diseases and death of some organisms.Therefore,detection of Cu in water and food is of great significance.Classical methods for determination of Cu,such as atomic spectrometries and mass spectrometry,are highly selective,sensitive and accurate.However,they are also expensive and cumbersome with high operational cost,thus not suitable for field application.Spectrophotometric and electrochemical methods both have the advantages of simple,light,low cost and easy handling,which makes them appropriate for rapid analysis in field.With unique physical and chemical properties,metal nanoparticles have become a powerful reagent in spectrophotometric and electrochemical detection of Cu.The reported methods using metal nanoparticles to detect Cu still have some shortcomings,such as complex procedure for synthesis of metal nanoparticles,low sensitivity,slow detection speed,or difficult to be applied in field.Therefore,the determination of Cu with metal nanoparticles still has room for improvement.The purpose of this research is to develop new analytical methods based on metal nanoparticles for copper ions(Cu2+),which would be applied in water analysis.The main contents and results of the research are as the follows:(1)The silver nanoparticles(AgNPs)were catalytically etched by Na2S2O3 in the presence of Cu(NH3)42+,and the absorbance at 401 nm was decreased.Based on this,a flow-batch analysis technique and a spectrophotometric method were integrated for determination of Cu2+.The limit of detection(LOD)was as low as 0.24 ?g/L,and the linear range was 0.5-35 ?g/L.The relative standard deviation(RSD,n=7)for samples at Cu2+ concentrations of 10 ?g/L was 1.21%and for 25 ?g/L was 1.03%.The proposed method was successfully applied to analyze Cu2+ in tap water,lake water,rainwater,bottled water and leaf soaking water samples.The results were in good agreement with those obtained with graphite furnace atomic absorption spectrometry(GFAAS).The proposed method had the advantages of high automation,sensitivity,simplicity,cheapness and rapid detection,which could be developed into a method for rapid determination of Cu2+ in environmental water.(2)Based on the aggregation of L-Cysteine modified gold nanoparticles(L-Cys-AuNPs)induced by Cu2+,a paper-based colorimetric method for Cu2+detection was developed.L-Cys-AuNPs was coated onto a filter paper for testing Cu2+,and the color change was analyzed with software Image J.The LOD was 0.09 mg/L,and the linear range was 0.1-10 mg/L.The RSD(n=5)was 6.6%for 1 mg/L Cu2+ and 3.5%for 5 mg/L Cu2+.The proposed method was of low cost,less reagent consumption and easy to use,and had been applied to the determination of total copper and dissolved copper in mineral wastewater.The results agreed with those obtained with China National Environmental Protection Standars HJ485-2009.The proposed method had good application prospect on field analysis of Cu2+ in industrial wastewater or polluted water.(3)With cyclic voltammetry,gold nanoparticles(AuNPs)were deposited onto a glassy carbon electrode.A square wave anodic stripping voltammetry for the determination of Cu2+ using the modified electrode was developed.The LOD was 1.3?g/L,and the linear range was 2-30 ?g/L.The RSD(n=5)was 6.7%for 10 ?g/L Cu2+and 4.2%for 30 ?g/L.The proposed method was used to the determination of Cu2+ in the midstream of Minjiang River,and the results had not significant difference with those obtained with GFAAS.The proposed method was simple,inexpensive and fast,and could be developed for field determination of Cu2+ in environmental water. |
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